Add t/ back to .gitignore

Keep t/ directory ignored so imported Perl5 tests are not tracked by git

Author: fglock

.gitignore

@@ -25,6 +25,10 @@ src/test/_Deparsed_XSubs.pm
 # Ignore Perl test suite files
 perl5/
 
+# Ignore the t/ directory (Perl test suite copied from perl5/t/)
+# These should be synced from perl5 repo, not committed here
+t/
+
 # Ignore perl5_t/ directory (module tests from perl5/lib/*.t)
 # These are synced from perl5 repo via sync.pl, not committed here
 perl5_t/